Collapsible conduit core



Sept. 8, 192B.

H. E'. UNIDAS COLLAPSIBLE CONDUI'I CORE Filed April 7, 1926 2 Sheets-Sheet l fag@ 1 .1,684,497 H. E. LnNDAs I COLLAPSIBLE CONDUIT CORE sept 1s, 192s.

Filed April '7, 1926 2 Sheets-Sheet 2 ls f "ner portion and a collapsible outer portion.

'being preferably expansible. Forming 4a 'molded portion of conduit.

tion vof an inflated oore,-showing alinethod "theends of lsaid core, a weighting chain belapsible core in position therein.

Patented Sept. 18, 1928.

. UNITED HENRYE. LINDAsoF coronen'osrnines, COLORADO.

GOLLAPSIBLE CONDUIT lCORE.

Application 'led April 7,

'The present invention relates to 'conduit construction, and more particularly to :molded conduit construction, where a. 'collapsible core is used to formthe central opening of a conduit. An object of the present invention fis to mold a conduit of ceinentitious material over a collapsible core, the core being constructed to facilitate its withdrawal after the material `forming tlie'conduit has set.

Another 'Objectis to mold a conduit overa collapsible core, comprising an inflatable in# In orderto attain these objects, there is provided, in accordance with one feature of `the' invention7 an elongated inflatable sleeve which may be of rubbei1 or fabric. said sleeve sheath over this sleeve is a. second sleeve which may be of fabric, said `sleeve 'having the diameter when inflated ofthe interior of a conduit of which the Icombined sleeves kform the central core.

These and other featureslof the invention, not specifically mentioned, will be 'more lfully brought out in the following description'and the accompanying drawing, wherein:

Figure l, is a view in longitudinal section `through a `conduit lmade in accordance 'withl fthe present invention, showing the collapsilble core in the process of being withdrawn therefrom.

`Figure 2, is a. view similar to Figure 1, showing the core in position infa freshly ,Figure 3, 'is an enlarged ylongitudinal seco'f "mounting a wire thcreinand of clamping ing` shown in position therein.

Figure 4, is a view in cross section ofla molded portion of concrete, showing the col 'perspective fboii'red. but usually the trench it 1926. .semaine 100,267.

ia@ conduit'df `ywhich the zsleeve forms' a .fpo'rtion lof the core, the sleeve 'beingsoniewhat longer than a section of conduit which it is desired to'niold An inner'sleeveQ is of inflatable material, suchV as rubber or tightly woven fabric. Where fabric is used for the inner sleeve vand water is used as an inflating medium, asmallquantty of water seeps through the oute'r sleeve lan'd'ten'ds to floatjiieatcement from the ceinentitious'mi'xture of which vthe conduit is moulded finto close proxiihity to lthe core. When the core is -with'drawn l'eavesla smooth, strong 'finish on :the interior 'of the conduit.

The 'structural features of the sleeves 'are unimportant,`however,

since the invention is intended to include any structure 'within the yscope of the appended claims.

Aninflating'tube 3 -I'n'ay be clamped in one end ofthe inner sleeve to be iii openf'c'ommunication with the interior'thereof'and to form a tight joint therewith, as by Ymeans 'of 'la clamp e. The 'outer sleeve l may also' be 'embraced bythe clamp y4: to hold it in rposition. -A wire 'extends longitudinally of the interior ofthe sleeves f1 and 2,a glande, or

'other suitable lrneans, being vused to foi-rn en air-tight sea] between the wi/treffend the tube f3. A 'valve 7 'provides means for eonneetingra pressure hose, vnot shown, =to thetube 'by means of which 'air or water nntler `pressure may be introduced into the interior "of Zthe `core t'o inflate it. rIlheends of both sleeves 1 and'2 within the conduit are secured as by meansoifa second clamp 8, to elosethemd of the inner sleeve. A second inner sleeve 9 jis connected to the clamp Vfor1afpi'irpo`se to loe brought 'ont later in 'the specification. The

ends of the inner sleeves Zand Qniay vbe "formed to closely lencircle the tube f3 Vatene end and the wire 5 at the other to facilitate "the rmaking of v'a Vvtight c'onn'ectio'n therewith. The ends of tlieouter sleeve l |`are.'liw'ever, 'left'the saine s'iie Vas the remainder jef vthe 4sleeve vso that the ends be'pened -iijo to permitih@ withdrawn therethrough ef the Vinner sleeveQ.

In usingfthe fc'ore, a. 'trench "or trough 10- is formed of a fsizeto mold thedesire'd conduit therein. A -ni'ta'llicor wooden fr'il of an oreimry type, not shown, 4iiii'y be ipiaced finteriorlyfo'f the vditch 'o'rtrough to "comprise La mold in whieh ehefmat'eriai 'for the.' 'conjdaitf'is i-f net the enfile. temine@ plate *il may (ill Y conduit to be used in be placed across the end of a section of conduit which it is desired tomold, and a quantity of concrete, or other cemetitious material, poured along the bottom of the trench.

Then a bed of suiiicient thickness has been f poured, a core, such as that shown in Figure 3, is placed in position on the bed of concrete, the end ofthe core projecting through the retaining plate 11, as shown in Figure 2. Thev inner end of the core is positioned Within the portion of conduit previously pou-red, the ldivision between the old and new sections be ing indicated by the line 2O in Figure 2. The core is then iniiated by the introduction of air or water through the tube 3. Concrete, or other cementitious material, is then poured about the collapsible core to approximately the height shown in Figures 1, 2, and 4, and allowed to harden. 1

After the cementitious material has set, the valve 7 is opened, releasing the fluid from the interior oi' the core, whereupon the inner sleeve contracts due to its expansible nature sufiiciently to f'ee 'it from the outer sleeve 1. The clamp 4 is then removed, releasing the ends of the sleeves, and the gland 6 is released to free the wire- 5. After releasingthe fluid from the core, and opening up the end of the outer sleeve 1 to permit the withdrawal therethrough of the inner sleeve 2, the wire 5,

together with the inner sleeve 2, is .drawn n toward the open end of the conduit.

The clamp 81011 the innery end of the core is in engagement with the second inner sleeve 9, and asthe wire 5 with the first inner sleeve 2 is drawn out of the conduit it draws the first inner sleeve 2 out of the outer casing 1 and simultaneously inverts the outer casing upon itself, causing it to enshea-th the second inner sleeve 9. This is causedby the slight adherence of the outer casing to the cementitious materia-l of the conduit, said outer sleeve being slowly pulled away` from the concrete as the end of the sleeve is drawn through the sleeve to invert it upon itself. The Wire 5 is preferably long enough that when the conduit is completed and thecollapsible .core is withdrawn, the wire will still remain in the drawing a cable therethrough.` 1 -v When the yfirst inner sleeve 2 is entirely removed from a molded section of conduit, the outer casing 1 will have been completely inverted upon itself and will ensheaththe secondinner sleeve 9, the first inner sleeve 2 being entirely withdrawn from the outer sleeve. By removing the clamp 8 and placing it on the other end of the second inner sleeve and the outer casing which covers it, and connecting the inflating tube and a new inner core in the same relativepositions as those shown in Figures 1 and 2 to this new assembly, theprocess may be repeated indefinitely.

In the making of long sections of conduit, and also where two or more passages are required in a conduit, it is sometimes necessary to weight the cores to make them ofsubstantially the same specific gravity as the cementitions material of which they are molded to prevent them from ioating from their proper position in the mold. This may be done by inserting a length of chain 12 in each of the inner sleeves or by using water, or other fluid, as an iniiating medium. When the chain weighting means alone is employed, the chain maybeleft permanently in the inner sleeves `and is provided with a connection v,14 at each end by which it may be attached to the central wire 5. i A Y A Anchor means are illustrated in Figures 5 and 7, having vertical rods 15 with offset portions at predetermined distances therein. The ends ofthe rods 15 may be forced into the bottom of the trench to be supported vertically thereby. Cross members 17,Yhaving hook-shaped end portions 18, are hooked into engagement with the `olset portions 16` of the vertical rods 15 to retain the cores in position during pouring of the conduit. The `rods may extend above the conduit, as shown ,in Figure 5, so that if futureA re uirements call for more passages in the con uit these may be constructed above the'original conduit,

.using the projecting Vupper portions of the yrods 15 to anchor the cores in position.

By` properly weighting the cores and anchoring them at required intervals, long sections of conduit having several passages therethrough may be readily constructed in the manner specified.

I claim: Y 1. A collapsible conduit core, comprising inner and outer casings, thev inner casing being inflatable and expansible, the outerA casing beiner invertible and comparatively non-expansible.

2. A collapsible conduit Vcore'composedof a. plurality of sleeves ensheathedone within the other, one of said sleeves being inflatable, and the other being invertible upon itself,

said core being removable from a cast conduit by withdrawing the inflatablel sleeve and inverting the other of said sleeves to withdraw it. l

' 3. v A collapsibleconduit core having a wire therein, the core being composed of an inner sleeve and an outer sleeve; said core being removable from a cast conduit by telescopically withdrawing the inner sleeve from the outer sleeve and simultaneously inverting the outer sleeve upon itself to withdraw it rom the conduit.

4. A collapsible conduit core having a collapsible casing an inflatable sleeve therein the inner sleeve bein removed by withdrawing it telescopically rom a cast conduit while the collapsible casing is inverted inwardly upon itself to Withdraw it.

5.v A collapsible conduit core, comprising an inner inflatable sleeve, a wire connected therethrough, and hermetioally sealed-thereto, and 7. A collapsible conduit core, Comprising an outer comparatively inexpansible sleeve, inner and outer sleeves, the inner sleeve being 10 an end of which may be opened to pass the inntab1e,`zind the outer sleeve being invertinner sleeve therethrough. ible independently of the inner sleeve.

6. A conduit core, comprising an outer In testimony whereof I aiiix my signature. sleeve, and an inner, inflatable s1eeve,s1idab1e forth.

Within the outer sleeve, for the purpose set HENRY E. LINDAS. 

